The present invention relates to a touch dimmer system of single or multiple-key embodiment for controlling the brightness of an electric lamp or plurality of lamps.
Known in the art is a dimmer comprising a variable voltage power supply having an input adapted to be connected to an alternating voltage and an output, a latching switch means having one terminal connected to the input and another terminal connected to the output and a control terminal to which a control voltage is applied for latching the switch in a closed condition at a preset time in a sub-cycle of the line alternating voltage. The switch means, which can be a triac, changes to an open state from a closed state to interrupt current flow to the output of the power supply during the zero crossing which terminates the alternating voltage sub-cycle. The control circuit requires a source of periodic signals and a counter to which signals are applied for incrementing and then decrementing the count in the counter between lower and upper counting limits in response to application of a level-setting constant voltage applied to an input of the control circuit for a period of time until the desired output voltage of the power supply is reached. When used to control a lamp, the variable voltage power supply functions for example, to light the lamp, by touching a step function signal generator momentarily. This causes the lamp to be lit at its previous brightness level. To change the brightness level of the lamp, the step function generator is held for a longer time whereupon the light cycles through brightness levels until the desired one is reached whereupon the step function signal generator can be released and memory will retain the latest brightness level.
Also known is a dimmer comprising a microcomputer controlled light level intensity switch which is operated by a pair of non-latching switches which provide inputs to the microcomputer. The non-latching switches may be arranged as upper and lower switches on a rocker panel. When the switch is depressed in either the up or down direction with a brief tap, the microcomputer will cause the level of light intensity to automatically advance or "fade" toward a predetermined level. The fade rate is adjustable. Also, if the switch is tapped again while the light intensity is fading towards the preset level (which is set by holding the switch as the light level changes until the desired level is reached), the microcomputer will halt the fading and cause the light intensity level to abruptly shift to the preset level.
Also known is an electric dimmer with touch keys wherein a triac which can be used to regulate the brightness of lamps is controlled by an integrated circuit having a voltage controlled oscillator therein which responds to currents generated by finger touching of the dimmer touch keys as well as the line voltage to assure that a specific phase angle drive to the triac is applied. A memory circuit retains this angle indefinitely, in the absence of power interruption.
Still another known dimmer includes a control circuit for raising or lowering the intensity of a group of lights at a desired fade rate. The control circuit comprises at its inputs a variable frequency pulse generator and a raise/lower enable circuit. The raise/lower enable circuit provides a first enabling signal which enables a gating means to apply the clock pulses generated by the pulse generator means to the up input terminal of an up/down counter. Another enabling signal enables a gate means which applies the clock pulses generated by the pulse generator to the down input terminal of the up/down counter. The up/down counter calculates the difference between the number of up pulses and down pulses and generates a digital signal representative of the evaluation. Finally, digital to analog converter means generate an analog output control signal to control the fade rate of the light through the dimmer.
Yet another known dimmer includes a control circuit for a triac-type dimmer which in turn controls a plurality of lamps. A trigger pulse generator provides a trigger pulse for each triac-type dimmer, the phase angle of which pulse is a function of a binary encoded intensity indicating signal. The intensity indicating signal and a time based signal are combined in a trigger pulse generator to produce the trigger pulse which is applied to the gate of the triac, with the object being to deliver the appropriate power to the lamp to maintain its desired brightness regardless of changes in the line voltage.
Still another known dimmer discloses a touch control switch for incandescent lighting wherein a triac controls the brightness of an incandescent lamp, with the triac having a gate input circuit comprising a counting circuit with a forward stepping input and a digital control input, as well as a trigger pulse generating circuit for controlling the conduction of the triac in accordance with the condition of activation of the digital control output.